What is the only letter that doesn’t appear in the periodic table?
J
Q
X
Z
The letter J is the only letter not used in any element symbol or name in the periodic table.
What temperature in Celsius does Mercury, the only liquid metal at room temperature, freeze?
-38.83°C
-42.15°C
-45.67°C
-39.91°C
Mercury remains liquid at room temperature and freezes at precisely -38.83°C, making it unique among metals.
Which element, discovered in 1939, was the first to be produced artificially?
Technetium
Plutonium
Francium
Americium
Technetium was the first artificial element, synthesized by Carlo Perrier and Emilio Segrè at the University of California, Berkeley.
How many elements were known to exist when Mendeleev created his first periodic table in 1869?
63
92
45
71
Mendeleev organized 63 known elements by atomic weight, leaving gaps for undiscovered elements that he correctly predicted would be found.
What percentage of the human body’s atoms are hydrogen?
0.62
0.47
0.55
0.71
While most of our mass is oxygen, 62% of all atoms in the human body are hydrogen atoms, primarily in water molecules.
Which noble gas was discovered on the Sun before Earth?
Helium
Neon
Argon
Krypton
Helium was first discovered in 1895 through spectral analysis of sunlight, before it was found on Earth in 1895.
Which element was named after Einstein and has atomic number 99?
Einsteinium
Nobelium
Fermium
Californium
Einsteinium (Es) was discovered in the debris of the first hydrogen bomb test in 1952 and named after Albert Einstein in 1955.
How many naturally occurring elements are there on Earth?
94
92
98
90
There are 92 naturally occurring elements, with all others being artificially created in laboratories.
Which element was named after the scientist Marie Curie?
Curium
Polonium
Radium
Ruthenium
Curium (Cm), element 96, was named after Marie and Pierre Curie in 1944 by Glenn Seaborg.
What percentage of the universe is hydrogen?
0.75
0.85
0.9
0.73
Hydrogen makes up about 75% of the universe’s elemental mass, with helium making up most of the remainder.
In what year was the last naturally occurring element discovered?
1925
1939
1932
1945
Francium, discovered by Marguerite Perey in 1939, was the last naturally occurring element found.
Which element has the highest melting point?
Tungsten
Osmium
Rhenium
Tantalum
Tungsten has the highest melting point of any element at 3,422°C (6,192°F).
What is the atomic number of Ununoctium, the heaviest element ever created?
118
116
115
117
Ununoctium (now Oganesson) was first synthesized in 2002 and is the heaviest element created, with atomic number 118.
How many elements in the periodic table are named after places in Europe?
16
12
14
18
16 elements are named after European locations, including Germanium, Polonium, and Francium.
What year was the periodic table first published by Mendeleev?
1869
1871
1865
1873
Dmitri Mendeleev published his first periodic table in 1869, organizing elements by atomic weight and chemical properties.
Which element is essential for human life but deadly as a gas?
Chlorine
Nitrogen
Fluorine
Bromine
Chlorine is essential in our bodies as chloride ions but is deadly as a gas, used as a chemical weapon in WWI.
What percentage of Earth’s crust is oxygen?
0.466
0.423
0.489
0.448
Oxygen makes up 46.6% of Earth’s crust by mass, making it the most abundant element in the crust.
How many synthetic elements were created between 1940 and 1960?
10
8
12
6
The period 1940-1960 saw the creation of 10 synthetic elements, largely due to nuclear research during and after WWII.
What is the most expensive naturally occurring element per gram?
Francium
Californium
Polonium
Plutonium
Francium is the most expensive natural element, worth about $1 quadrillion per gram, though it’s so unstable it can’t really be collected.
How many elements are required for all known forms of life?
25
28
22
30
25 elements are essential for life, including carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur as the main ones.
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